Rihanna has been named Billboard's Top Pop Artist of the last 20 years, in an analysis of her chart performance.

Rihanna has been named Billboard's Top Pop Artist of the last 20 years.

The 'Diamonds' hitmaker tops the US music magazine's list of the most successful artists in the history of its Pop Songs chart, which started on October 3, 1992.

The magazine awarded her top spot for her achievements on the chart, which include 34 appearances with 21 top ten hits, and nine number one songs, an accolade she shares with Katy Perry, placed at sixth on the list.

The top ten was dominated by solo women singers, with Usher the only male, and Black Eyed Peas the only group.

Katy comes in next, and New York based radio programme director Sharon Dastur, reminisced about the first time she worked with her.

She said: ''Katy's very first single, 'I Kissed a Girl,' had just recently come out and we were playing it on [radio station] Z100. We started to feel an early buzz on the song, but the masses still weren't that familiar with who Katy was. We invited her to come on-stage at our Jingle Ball to help introduce one of the acts performing.

''We weren't sure if the crowd would be familiar with her by name, so we suggested that when she went out there, she should sing the hook of 'I Kissed a Girl' a capella. As soon as the crowd heard that, they sang every word along with her.

''Katy has told us that she'll always remember that moment.''

Rounding out the top ten were Usher in seventh, followed by Black Eyed Peas, Janet Jackson and Madonna.